//! Semantic Tag domain model
//!
//! Implementation of the advanced semantic tagging architecture described in the whitepaper.
//! This replaces the simple tag model with a sophisticated graph-based system that supports
//! polymorphic naming, contextual resolution, and compositional attributes.

use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use specta::Type;
use std::collections::HashMap;
use uuid::Uuid;

use super::resource::Identifiable;

/// A tag with advanced capabilities for contextual organization
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub struct Tag {
	/// Unique identifier
	pub id: Uuid,

	/// Core identity
	pub canonical_name: String,
	pub display_name: Option<String>,

	/// Semantic variants for flexible access
	pub formal_name: Option<String>,
	pub abbreviation: Option<String>,
	pub aliases: Vec<String>,

	/// Context and categorization
	pub namespace: Option<String>,
	pub tag_type: TagType,

	/// Visual and behavioral properties
	pub color: Option<String>,
	pub icon: Option<String>,
	pub description: Option<String>,

	/// Advanced capabilities
	pub is_organizational_anchor: bool,
	pub privacy_level: PrivacyLevel,
	pub search_weight: i32,

	/// Compositional attributes
	pub attributes: HashMap<String, serde_json::Value>,
	pub composition_rules: Vec<CompositionRule>,

	/// Metadata
	pub created_at: DateTime<Utc>,
	pub updated_at: DateTime<Utc>,
	pub created_by_device: Uuid,
}

/// Types of semantic tags with different behaviors
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub enum TagType {
	/// Standard user-created tag
	Standard,
	/// Creates visual hierarchies in the interface
	Organizational,
	/// Controls search and display visibility
	Privacy,
	/// System-generated tag (AI, import, etc.)
	System,
}

impl TagType {
	pub fn as_str(&self) -> &'static str {
		match self {
			TagType::Standard => "standard",
			TagType::Organizational => "organizational",
			TagType::Privacy => "privacy",
			TagType::System => "system",
		}
	}

	pub fn from_str(s: &str) -> Option<Self> {
		match s {
			"standard" => Some(TagType::Standard),
			"organizational" => Some(TagType::Organizational),
			"privacy" => Some(TagType::Privacy),
			"system" => Some(TagType::System),
			_ => None,
		}
	}
}

/// Privacy levels for tag visibility control
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub enum PrivacyLevel {
	/// Standard visibility in all contexts
	Normal,
	/// Hidden from normal searches but accessible via direct query
	Archive,
	/// Completely hidden from standard UI
	Hidden,
}

impl PrivacyLevel {
	pub fn as_str(&self) -> &'static str {
		match self {
			PrivacyLevel::Normal => "normal",
			PrivacyLevel::Archive => "archive",
			PrivacyLevel::Hidden => "hidden",
		}
	}

	pub fn from_str(s: &str) -> Option<Self> {
		match s {
			"normal" => Some(PrivacyLevel::Normal),
			"archive" => Some(PrivacyLevel::Archive),
			"hidden" => Some(PrivacyLevel::Hidden),
			_ => None,
		}
	}
}

/// Relationship between two tags in the semantic graph
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub struct TagRelationship {
	pub related_tag_id: Uuid,
	pub relationship_type: RelationshipType,
	pub strength: f32,
	pub created_at: DateTime<Utc>,
}

/// Types of relationships between tags
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub enum RelationshipType {
	/// Hierarchical parent-child relationship
	ParentChild,
	/// Synonym or alias relationship
	Synonym,
	/// General semantic relatedness
	Related,
}

impl RelationshipType {
	pub fn as_str(&self) -> &'static str {
		match self {
			RelationshipType::ParentChild => "parent_child",
			RelationshipType::Synonym => "synonym",
			RelationshipType::Related => "related",
		}
	}

	pub fn from_str(s: &str) -> Option<Self> {
		match s {
			"parent_child" => Some(RelationshipType::ParentChild),
			"synonym" => Some(RelationshipType::Synonym),
			"related" => Some(RelationshipType::Related),
			_ => None,
		}
	}
}

/// Rules for composing attributes from multiple tags
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub struct CompositionRule {
	pub operator: CompositionOperator,
	pub operands: Vec<String>,
	pub result_attribute: String,
}

/// Operators for combining tag attributes
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub enum CompositionOperator {
	/// All conditions must be true
	And,
	/// Any condition must be true
	Or,
	/// Must have this property
	With,
	/// Must not have this property
	Without,
}

/// Context-aware application of a tag to content
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub struct TagApplication {
	pub tag_id: Uuid,
	/// Context when the tag was applied (e.g., "geography", "technology")
	pub applied_context: Option<String>,
	/// Which variant name was used when applying
	pub applied_variant: Option<String>,
	/// Confidence level (0.0-1.0, useful for AI-applied tags)
	pub confidence: f32,
	/// Source of the tag application
	pub source: TagSource,
	/// Attributes specific to this particular application
	pub instance_attributes: HashMap<String, serde_json::Value>,
	/// When this application was created
	pub created_at: DateTime<Utc>,
	/// Which device applied this tag
	pub device_uuid: Uuid,
}

/// Source of tag application
#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Type)]
pub enum TagSource {
	/// Manually applied by user
	User,
	/// Applied by AI analysis
	AI,
	/// Imported from external source
	Import,
	/// Synchronized from another device
	Sync,
}

/// Result of merging tag applications during sync
#[derive(Debug, Clone, Serialize, Deserialize, Type)]
pub struct TagMergeResult {
	pub merged_applications: Vec<TagApplication>,
	pub conflicts: Vec<TagConflict>,
	pub merge_summary: String,
}

/// Conflict that occurred during tag merging
#[derive(Debug, Clone, Serialize, Deserialize, Type)]
pub struct TagConflict {
	pub tag_id: Uuid,
	pub conflict_type: ConflictType,
	pub local_value: serde_json::Value,
	pub remote_value: serde_json::Value,
	pub resolution: ConflictResolution,
}

#[derive(Debug, Clone, Serialize, Deserialize, Type)]
pub enum ConflictType {
	AttributeValue,
	Context,
	Confidence,
}

#[derive(Debug, Clone, Serialize, Deserialize, Type)]
pub enum ConflictResolution {
	UseLocal,
	UseRemote,
	Merge,
	RequiresUserInput,
}

/// Pattern discovered through usage analysis
#[derive(Debug, Clone, Serialize, Deserialize, Type)]
pub struct OrganizationalPattern {
	pub pattern_type: PatternType,
	pub tags_involved: Vec<Uuid>,
	pub confidence: f32,
	pub suggestion: String,
	pub discovered_at: DateTime<Utc>,
}

#[derive(Debug, Clone, Serialize, Deserialize, Type)]
pub enum PatternType {
	FrequentCoOccurrence,
	HierarchicalRelationship,
	SemanticSimilarity,
	ContextualGrouping,
}

impl Tag {
	/// Create a new semantic tag with default values
	pub fn new(canonical_name: String, created_by_device: Uuid) -> Self {
		let now = Utc::now();

		Self {
			id: Uuid::new_v4(),
			canonical_name: canonical_name.clone(),
			display_name: None,
			formal_name: None,
			abbreviation: None,
			aliases: Vec::new(),
			namespace: None,
			tag_type: TagType::Standard,
			color: None,
			icon: None,
			description: None,
			is_organizational_anchor: false,
			privacy_level: PrivacyLevel::Normal,
			search_weight: 100,
			attributes: HashMap::new(),
			composition_rules: Vec::new(),
			created_at: now,
			updated_at: now,
			created_by_device,
		}
	}

	/// Get the best display name for this tag in the given context
	pub fn get_display_name(&self, context: Option<&str>) -> &str {
		// If we have a context-specific display name, use it
		if let Some(display) = &self.display_name {
			return display;
		}

		// Otherwise use canonical name
		&self.canonical_name
	}

	/// Get all possible names this tag can be accessed by
	pub fn get_all_names(&self) -> Vec<&str> {
		let mut names = vec![self.canonical_name.as_str()];

		if let Some(formal) = &self.formal_name {
			names.push(formal);
		}

		if let Some(abbrev) = &self.abbreviation {
			names.push(abbrev);
		}

		for alias in &self.aliases {
			names.push(alias);
		}

		names
	}

	/// Check if this tag matches the given name in any variant
	pub fn matches_name(&self, name: &str) -> bool {
		self.get_all_names()
			.iter()
			.any(|&n| n.eq_ignore_ascii_case(name))
	}

	/// Add an alias to this tag
	pub fn add_alias(&mut self, alias: String) {
		if !self.aliases.contains(&alias) {
			self.aliases.push(alias);
			self.updated_at = Utc::now();
		}
	}

	/// Set an attribute value
	pub fn set_attribute<T: Serialize>(
		&mut self,
		key: String,
		value: T,
	) -> Result<(), serde_json::Error> {
		let json_value = serde_json::to_value(value)?;
		self.attributes.insert(key, json_value);
		self.updated_at = Utc::now();
		Ok(())
	}

	/// Get an attribute value
	pub fn get_attribute<T: for<'de> Deserialize<'de>>(
		&self,
		key: &str,
	) -> Result<Option<T>, serde_json::Error> {
		match self.attributes.get(key) {
			Some(value) => Ok(Some(serde_json::from_value(value.clone())?)),
			None => Ok(None),
		}
	}

	/// Check if this tag should be hidden from normal search results
	pub fn is_searchable(&self) -> bool {
		match self.privacy_level {
			PrivacyLevel::Normal => true,
			PrivacyLevel::Archive | PrivacyLevel::Hidden => false,
		}
	}

	/// Get the fully qualified name including namespace
	pub fn get_qualified_name(&self) -> String {
		match &self.namespace {
			Some(ns) => format!("{}::{}", ns, self.canonical_name),
			None => self.canonical_name.clone(),
		}
	}
}

impl TagApplication {
	/// Create a new tag application
	pub fn new(tag_id: Uuid, source: TagSource, device_uuid: Uuid) -> Self {
		Self {
			tag_id,
			applied_context: None,
			applied_variant: None,
			confidence: 1.0,
			source,
			instance_attributes: HashMap::new(),
			created_at: Utc::now(),
			device_uuid,
		}
	}

	/// Create a user-applied tag application
	pub fn user_applied(tag_id: Uuid, device_uuid: Uuid) -> Self {
		Self::new(tag_id, TagSource::User, device_uuid)
	}

	/// Create an AI-applied tag application with confidence
	pub fn ai_applied(tag_id: Uuid, confidence: f32, device_uuid: Uuid) -> Self {
		let mut app = Self::new(tag_id, TagSource::AI, device_uuid);
		app.confidence = confidence;
		app
	}

	/// Set an instance-specific attribute
	pub fn set_instance_attribute<T: Serialize>(
		&mut self,
		key: String,
		value: T,
	) -> Result<(), serde_json::Error> {
		let json_value = serde_json::to_value(value)?;
		self.instance_attributes.insert(key, json_value);
		Ok(())
	}

	/// Check if this application has high confidence
	pub fn is_high_confidence(&self) -> bool {
		self.confidence >= 0.8
	}
}

/// Error types for semantic tag operations
#[derive(Debug, thiserror::Error)]
pub enum TagError {
	#[error("Tag not found")]
	TagNotFound,

	#[error("Invalid tag relationship: {0}")]
	InvalidRelationship(String),

	#[error("Circular reference detected")]
	CircularReference,

	#[error("Conflicting tag names in namespace: {0}")]
	NameConflict(String),

	#[error("Invalid composition rule: {0}")]
	InvalidCompositionRule(String),

	#[error("Serialization error: {0}")]
	SerializationError(#[from] serde_json::Error),

	#[error("Database error: {0}")]
	DatabaseError(String),
}

// Implement Identifiable for normalized cache support
impl Identifiable for Tag {
	fn id(&self) -> Uuid {
		self.id
	}

	fn resource_type() -> &'static str {
		"tag"
	}

	fn sync_dependencies() -> &'static [&'static str] {
		&[] // Tags are a simple resource backed by the tags table
	}
}
